Mixing machine



March 2, 1943.

E. P. RocHFoRD Erm. 2,312,444

MIXING MACHINE Filed April 20, 1942 l l /B ff 89- lv! i l/85 3 Sheets-Sheet 1 Ku/ Wassen INVENTORS Y w Gb.

ATTORNEY March 2, 1943. E. P. RocHFoRD Erm. 2,312,444

MIXING MACHINE Filed April 20, 1942 5 Sheets-Sheet 2 Kur Wassen INVENTORS ma fxm.

ATTORNEY March Z, 1943. E, P RQCHFORD ErAL 2,312,444

MIXING MACHINE Filed April 20, 1942 3 Sheets-Sheet 3 FIG. 5

FIG. 7

FIG. 6

Kuri' Wassen IN VENTORS M Qs. fmul.

FICE. 8

ATTORNEY Patented Mar. 2, 1943 2,312,444 MIXING MACHINE Edmund P. Rochford, Kingston, N. Y., and Joseph Stuart, II, and Kurt Wassen, Wilmington, Del., assignors to Hercules Powder Company, Wilmington, Del., a corporation of Delaware Application April 20, V1942, Serial No. 439,626-

Claims.

This invention relates to a mixing machine and, more particularly, to a mixing machine for mixing explosive compositions.

Fulminate compositions are customarily mixed by hand due to the hazardous nature of the operation and the insumciency of safe mechanical equipment. Hand mixing is extremely detrimental to the health and safety of the persons performing the mixing operations but, heretofore, it has remained the only continuously successful method for satisfactorily mixing this type composition.

It is, therefore, a principal object of this invention to provide a machine for mixing fulminate compositions which insures an intimacy of mixture equal or superior to that obtained by hand methods and also insures health and safety protection for persons performing the operation.

A further object of this invention is the provision of mechanism for efliciently. safely, and expeditiously mixing explosive compositions.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

Generally described, the present invention comprises a mixing machine having in combination a mixing crank having a driving connection with a. cam shaft; a series of cams aiixed to the cam shaft; a series of lever arms reciprocally actuated by said cams; a series of cords each of which has one end connected to a respective lever arm; a flexible mixing mat having distended ends, each end of which is connected to the other respective end of each of the cords, said mat adapted to mix a material disposed thereupon in accord-ance with the reciprocating movement of the lever arms; a dumping crank integral with a dumping cam shaft; and a series of dumping cams aflixed to the dumping cam shaft, said dumping cams adapted to actuate the lever arms to form a declined trough of the mixing mat whereby the mixed material is discharged therefrom.

A preferred embodiment of the invention has been shown for purposes of illustration and description and is shown in the accompanying drawings forming a part of the specification wherein reference symbols refer to like parts wherever theyvoccur;

Fig. 1 is a side elevational view of the mixing machine with the protective 'wallbetween the operating compartment and the mixing compartment shown in section.

Fig. 2 is a part, side elevational view of the le ver arm actuating mechanism with the supporting brackets for the lever arms and the housing of the cam box removed to clearly show the operating mechanism.

Fig. 3 is a front elevational view of the mechanism shown in Fig. 2.

Fig. 4 is a plan View of the mixing table and mixing mat.

Fig. 5 is a plan view of Fig. 4 showing the rear corner of the mixing mat in a lifted position;

Fig. 6 is a plan view of Fig. 4 showing the left hand corner of the mixing mat in a lifted position.

Fig. 7 is a plan view of Fig. 4 showing the right hand corner of the mixing matin a lifted position.

Fig. 8 is a front elevational view of the mixing In Figs. 1, 2 and 3, a protective wall I separates an operating compartment A and 'a mixing compartment B and has a mounting plate 3 rigidly secured thereto. A cam box housing 5 and lever supporting brackets 1 are rigidly amxed to the mounting plate 3. The cam box housing 5 has journalled therein a mixing handle shaft 9, a gear shaft II, a mixing. cam shaft I3, a. rocker arm shaft I5 and a dumping handle shaft I1. A mixing handle I9 is rigidly secured to the mixing handle shaft 9. A pinion 2| rigidly secured to the shaft 9 engages a gear 23 which is rigidly secured to the shaft II. A pinion 25 secured to the shaft II engages a gear 21 secured to the shaft I3. Cams 29, 3| and 33 are affixed to and radially disposed equi-angularly about the cam shaft I3. These cams engage rollers 35, 31 and 39, respectively, on the rocker arms 4I, 43 and 45. The rocker arms are pivoted at one end to the rocker arm shaft I5 and are engaged at the other end by articulated pushl rods 41, 49 and 5I, respectively. These rods are pivotally connected at their upper ends to lever arms 53, 55 and 51 respectively which are, in turn, pivotally connected to a lever arm shaft 59 which is journalled in the supporting brackets 1. Adjustable counter-balances 6I, 63 and 65 are afdxed'to the lever arms 53, 55 and 51, respectively. Cord holders 61, 69 and 1I are rigidly secured to the lever anns 53, 55 and 51, respectively. Cords 13, 15, and 11 are ailxed to the cord holders 61, 59 and 1I, respectively, the cords extend through a conduit 19, which extends through the protective wall I, and engage a plurality of pulleys 8l which are aflixed to the conduit 19. A cord guard 83 is aixed to the conduit 19 to insure retention of the cords in the pulley grooves. The cords 13, 15, and 11 extend downwardly from the pulleys and are connected to a triangular ilexibie mixing 93 (Fig. 4).

erably of plastic material, supports the rubber Amixing mat 05 and has a discharge opening 0l extending therethrough. The mixing table 93 is suitably mounted to the protective wall I by angle brackets 81. A screen 99 is disposed beneath the discharge opening 95 and suitable rubber chutes are disposed adjacent thereto to direct the fines and tailings intorubber receptacles |03 and |05, respectively.4 Supporting structure represented by |01 is provided to support the rubber receptacle |03 and also serves as a receiving vessel for stray-material. Referring now, more particularly, to Figs. 1 to 8 inclusive, when the mixing handle i9 is rotated, the lever arms l2, 05 and 51 as actuated by the cams 29, 0| and 03, respectively, impart a sequentially reciprocating movement to the corners 01, 09 and Il, respectively, of the rubber mixing mat 05. This, in turn, imparts a mixing motion to the material disposed upon the rubber mixing mat 05. because as each corner of the rubber mixing mat is lifted, the material disposed on that portion of the mat rolls down the declined surface thus formed and by sequential lifting and lowering of the corners, the material is rolled back and forth and intimately mixed (Figs. 5, 6 and 7). When the cams are not actuating the lever arms, the mat 05 flatly reposes on the mixing table The rubber mixing mat 05 has an increased thickness |09 about its periphery with the exception of a small portion, represented by through which the mixed material slides when it is dumped, as will be hereinafter explained. 'I'he increased thickness |09 about the periphery of the mat 85 prevents any particles of material from rolling off the mat during the mixing operation. A

After the material has been thoroughly mixed, a dumping handle ||9 which is rigidly secured to the dumping handle shaft |1 is rotated a part turn. Cams H5, ||1 and I|9 are amxed to the shaft l1 and these cams engage rollers |2|, |23 and |25, respectively, on the rocker arms 4|, 43

and 49. This movement of the dumping handlel I I3 imparts a movement to the lever arms 53, I!

and 51,by connection with the appurtenant members heretofore described which. in association with the cords 1l, 15 and 11, causes the rubber mat 05 to assume a configuration substantially as illustrated in Fig. 1 (shown out of function) and Fig. 8. In this position, a declined trough is formed of the rubber mat 95 and the mixed material disposed thereupon slides from the mat, into and through the discharge opening 95 in the Y mixing table 99. A protrusion |21 is provided on the cam ||1, the function of which is to impart a jerking movement to the cord when the roller |23 rides over the protrusion. This jerking movement overcomes the inertia of the mixed material, thereby considerably reducing its angle of repose and the frictional coelcient between the mixed material and the rubber mat 05 so that it is more readily discharged.

An example of the operation of the invention is given for the mixing of explosive compositions. An operator enters the mixing compartment and places the ingredients of the composition upon the rubber mixing mat. He then proceeds to the operating compartment wherein he cranks the mixing handle a predetermined number of times to thoroughly mix the ingredients. After the mixing operation has been concluded, the operator manipulates the dumping handle which causes the rubber mixing mat to discharge the mixed material through the .mixing table top. The mixed material falls onto a sieve which'separates the coarse from the fine particles of material. 'I'he separated particles of material are collected in rubber receptacles. The operator reenters the mixing compartment, removes the material from the receptacles or substitutes empty receptacles therefor and another cycle is started. f

It is evident that there are numerous factors which will influence conditions for the most satisfactory operation of the invention, the actual limits of which cannot be established except by detailed study of each set of materials and in the intermediate and finished products involved. For example, for certain types of mixing, the mixing table may be dispensed with entirely. With this arrangement, the mixing mat is suspended from the cords and the material to be mixed is dumped into the concavity formed by the suspended mat. The number of points in suspension on the mat is immaterial so long as the material disposed on the mat is given a suitable rolling motion and the mat is adapted to effect discharge of the mixed material.

The advantages of the present invention reside in the fact that the operator at all times is protected from hazards. inherent to the mixing operation and the mixing is accomplished with a degree of uniformity not otherwise obtainable. Furthermore, the materials of construction utilized 'in the mixing compartment may be composed of non-pyrophoric materials which greatly reduce the hazards incident to accidental ignition.

While the present invention is directed generally to the mixing of various compositions, it is directed primarily to the mixing of explosive compositions andV particularly primary explosives or initiators as, for example, mercury fulminate or diazodinitrophenol with an oxygen carrier such as potassium chlorate.

It will be seen, therefore, that this invention may be carried outby the use of'various modifications and changes without departing from its spirit and scope.

Whe we claim and desire to protect by Letters Patent is:

1. A mixing machine having in combination a mixing crank having a driving connection with a cam shaft; a series of cams amxed to the cam shaft; 'a series of lever arms reciprocally actuated by said cams; a series of cords each of 'which has one end connected to a respective lever arm; a flexible mixing mat having distended ends, each end of which is connected to the other respective end of each of the cords, said mat adapted to mix a material disposed thereupon in accordance with the reciprocating movement of the lever arms; a dumping crank integral with a dumping cam shaft; and a series of dumping cams aiiixed to the dumping cam shaft, said dumping cams adapted to actuate the lever arms to form a declined trough of the mixing mat whereby the mixed material is discharged therefrom.

2. In combination with a machine of the class described an operating compartment and a mixing compartment having a protective wall disposed therebetween; means disposed within the operating compartment for sequentially and reciprocally actuating three lever arms; means associated with said lever arms and extending through the protective wall for actuating a triangular, equilateral, mixing mat, each corner of which is reciprocated upward and downward in accordance with movement of its respective lever arm; a mixing table, for supporting the mixing mat. having a discharge opening therethrough; and means associated with said lever arms tor actuating the lever arms to form a decllned trough of the -mixing mat whereby material is discharged from the mixing mat into the discharge opening.

3. A mixing machine having in combination a mixing crank having a driving connection with a cam shaft; a 'series of cams aflixed to the cam shaft; a series oi' lever arms reciprocally actuated by said cams; a series of cords each of which has one end connected to a respective lever arm; a flexible mixing mat having distended ends, each end of which is connected to the other respective end of each of the cords, saidmat adapted to mix a material disposed thereupon in accordance with the reciprocating movement of the lever arms; a table, for supporting the mixing mat, having a discharge opening therethrough; a dumping crank integral with a dumping cam shaft; and a series of dumping cams amxed to the dumping cam shaft, said dumping cams adapted to actuate the lever arms to forma declined trough of the mixing mat whereby material is discharged from the mixing mat into said discharge opening.

4. In combination with a machine of the class described an operating compartment and a mixing compartment having a protective wall disposed therebetween; means disposed within the operating compartment for sequentially and reciprocally actuating a plurality of lever arms; means associated with said lever arms and extending through the protective wall for actuating a mixing mat, a portion of which is reciprocated upwardly and downwardly in accordance Withvmovement of its respective lever arm; and means associated with said lever arms for actuating the lever arms to form a declined trough of the mixing mat whereby mixed material is discharged therefrom.

5. In combination with a machine of the class described an operating compartment and a mixing compartment having a protective wall dissposed therebetween; means disposed within the operating compartment for sequentially and reciprocally actuating a. plurality of lever arms; means associated with said lever arms and extending through the protective wall for actuating a mixing mat, a portion of which is reciprocated upwardly and downwardly in accordance with movement of its respective lever arm; a mixing table, for supporting the mixing mat, having a discharge opening therethrough; and means associated with said lever arms for actuating the lever arms to form a declined trough of the mixing mat whereby material is discharged from the mixing mat into the discharge opening.

4 EDMUND P. ROCHFORD.

JOSEPH STUART, II.- KURT WASSEN. 

